OFFSET
0,2
LINKS
Index entries for linear recurrences with constant coefficients, signature (0,201,0,-10100).
FORMULA
G.f.: 11*(1+x)/(1-101*x^2) - 10/(1-100*x^2);
a(n) = 201*a(n-2) - 10100*a(n-4);
a(n) = (11/2 + 11*sqrt(101)/202)*sqrt(101)^n + (11/2 - 11*sqrt(101)/202)*(-sqrt(101))^n - 10^(n+1)*(1+(-1)^n)/2;
a(n) = Sum_{k=0..n} binomial(floor(n/2), floor(k/2))*10^k.
MATHEMATICA
LinearRecurrence[ {0, 201, 0, -10100}, {1, 11, 111, 1111}, 18] (* Georg Fischer, Nov 07 2019 *)
PROG
(PARI) Vec((1+11*x-90*x^2-1100*x^3)/(1-201*x^2+10100*x^4) + O(x^25)) \\ Jinyuan Wang, Feb 28 2020
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Paul Barry, Jul 25 2004
EXTENSIONS
More terms from Jinyuan Wang, Feb 28 2020
STATUS
approved